Work continues on strains of mycoplasma originated from AIDS patients. Mycoplasma penetrans is isolated from the urogenital tract of patients with AIDS. Genetic analysis of this agent's DNA by liquid hybridization shows that this species is new. This organism has properties of adherence, hemadsorption, and cytadsorption and invades many different types of mammalian cells. Specific genetic clones and antibodies against this agent were prepared and used to probe infected tissues. Molecular and serological assays were developed for identifying mycoplasmas and the specific immunoresponses to these agents. These assays were used to assess the significance of infectivity and pathogenicity of this agent in humans. We developed a species-specific serological test for mycoplasmas. We continued to explore new tests for other mycoplasmas in addition to the existing ones for M.fermentens. M. penetrans, M. genitalium. and M. pneumoniae. We applied these serological tests to several clinical settings, including patients with HIV infection, nongonococcal urethritis (NGU), and sexually transmitted diseases (STDs), and patients who use intravenous drugs. We found a high prevalence of antibodies to M. penetrans in patients with Kaposi's sarcoma and antibodies to M. genitalium in patients with NGU. Using paired donor-recipient specimens, we also found that M.fermeniens and M. genitalium are transmissible through blood transfusions. In 1996 in a preliminary study in collaboration with scientists at the University of Medicine and Dentistry of New Jersey, we were able to show that the association of presence of antibody to M. genitalium with the sexual transmission of HIV was highly significant while agents for other STDs were not. This project is part of a long-term collaborative effort between this laboratory and Dr. Shyh-Ching Lo's at Armed Forces Institute of Pathology to investigate cofactors contributing to the pathogenesis of AIDS. A future interest for mycoplasma study is its contribution to neoplasm after long-term chronic infection. We have shown that some species of mycoplasma were able to transform cells in vitro after long-term cocultivation and activating oncogens.